The objective of this study is to demonstrate the effectiveness and tolerability of the buprenorphine transdermal system (20 mg) in comparison to the buprenorphine transdermal system (5 mg) and oxycodone immediate release in subjects with moderate to severe osteoarthritis pain currently treated with oral opioids. The double-blind treatment intervention duration is 12 weeks during which time supplemental analgesic medication (acetaminophen, ibuprofen, immediate release oxycodone) will be provided to all subjects in addition to study drug.